I have to guess many things, but can you adapt this?

Given a file named integrals.txt containing

NIntegrate[x^2,{x,0,3}]
NIntegrate[3x-4,{x,1,2}]
NIntegrate[Sin[x],{x,0,Pi}]
NIntegrate[Log[x+1],{x,1,2}]
NIntegrate[x*Sin[x],{x,0,3}]
NIntegrate[ArcTan[x],{x,1/2,1}]
NIntegrate[E^x/x,{x,1,5}]
NIntegrate[E^Sin[x],{x,0,3}]

(just plain ASCII text without any color highlighting, fonts, just the text, but I can't get an unformatted list to display here in any other way)

and a notebook containing this

In[1]:= dati =  StringSplit[Import["integrals.txt"], "\n"]

Out[1]= {"NIntegrate[x^2,{x,0,3}]", "NIntegrate[3x-4,{x,1,2}]", "NIntegrate[Sin[x],{x,0,Pi}]", "NIntegrate[Log[x+1],{x,1,2}]",
"NIntegrate[x*Sin[x],{x,0,3}]", "NIntegrate[ArcTan[x],{x,1/2,1}]", "NIntegrate[E^x/x,{x,1,5}]", "NIntegrate[E^Sin[x],{x,0,3}]"}

In[2]:= result = Map[ToExpression, dati]

Out[2]= {9., 0.5, 2., 0.909543, 3.1111, 0.318573, 38.2902, 6.05667}

In[3]:= ListPlot[result, Joined -> True]

Out[3]= ...PlotSnipped...

Where the In[n]:= are the actual lines I typed into the notebook and the Out[n]= lines were produced by Mathematica.

You either have to figure out where to put that file on your system so Mathematica can find it or you have to figure out how to tell Mathematica where you put it.